1. Field of the Invention
The present invention relates to a fixed-focus type photographic lens apparatus used in video cameras or electronic still cameras and, in particular, to a photographic lens apparatus in which a stop is disposed between an object and lens groups.
2. Related Background Art
Video cameras and electronic still cameras are configured such that an image of an object formed by way of a photographic lens apparatus is captured by a solid-state image pickup device, while a minute lens is formed on the image pickup surface of the solid-state image pickup device so as to increase the light quantity received thereby.
Accordingly, it is necessary for the luminous flux entering the image pickup surface of the solid-state image pickup device from the photographic lens apparatus to have an incident angle as small as possible. In other words, it is desirable for the exit pupil position of the photographic lens apparatus to be as far as possible.
Also, since a low-pass filter for preventing moire or a filter for cutting infrared light has to be disposed between the solid-state image pickup device and the photographic lens apparatus, it has been necessary for the photographic lens apparatus to have a sufficiently long back focus.
In recent years, in response to a demand for smaller video cameras and electronic still cameras, the size of the solid-state image pickup element has been reduced to such a dimension as 1/3 inch or 1/4 inch. Accordingly, there is a demand for further reducing the size of the photographic lens apparatus. However, when the photographic lens apparatus has a small size, it becomes difficult for its back focus and the distance between its image-forming surface and exit pupil to have sufficient values. Also, even when their sufficient values are secured, the optical performance of the apparatus may become insufficient.